This invention relates to the dispensing of beverages. It is particularly concerned to provide a means of dispensing carbonated beverages and, although not intended to be limited thereto, it will be more specifically described below with particular reference to carbonated beverages.
Carbonated beverages, which for the purpose of this application include carbonated water and carbonated flavoured drinks, e.g. colas and other carbonated mixtures of water and syrup, are required to have and to maintain a particular amount of carbonation in order to possess the desired qualities of flavour and texture in the drink. Thus, although the desired amount of carbonation may vary from beverage to beverage and may vary within relatively restricted limits for any particular beverage, it is important that these limits are not breached if the consumer is to receive a satisfactory product.
It will also be appreciated that the level of carbonation can be affected by the manner of dispense of the beverage. Carbon dioxide xe2x80x9cbreak outxe2x80x9d during dispense into, say a glass, causes frothing of the liquid and excessive frothing can lead to undue loss of carbonation and a less satisfactory product in the glass.
It is, therefore, an object of the invention to provide a means of dispensing a liquid which when applied to a carbonated liquid will reduce carbon dioxide break out.
Accordingly, the invention provides an apparatus to dispense a beverage, the apparatus comprising a valve through which the beverage is to be dispensed, actuation means to open and close the valve, means to propel the beverage from a source thereof through the open valve to a dispense point, flow rate determining means to monitor the rate of flow through the valve and pre-programmed control means responsive to the flow rate data provided to it by the flow rate determining means, the control means causing the actuation means to vary the opening of the valve to provide a predetermined variable rate of dispense, wherein the valve comprises a housing containing a passageway between an inlet and an outlet of the valve, a closure member movable in the passageway from a first position in which the valve is fully closed to a second position in which the valve is fully open, the closure member engaging the wall of the passageway to seal the passageway, the wall of the passageway or the closure member defining at least one groove, the groove having a transverse cross-section that increases in area in the downstream or upstream direction, whereby movement of the closure member from the first position towards the second position opens a flow channel through the groove.
The apparatus may also include a dispense tap through which the beverage can be dispensed into a suitable receptacle, e.g. a cup or glass.
The flow rate determining means may be any suitable means and may determine the flow rate by direct measurement or by calculation from a measured property. Thus, for example, the means may be, a turbine or a magnetic or ultrasonic or infra-red flow detector.
The control means will preferably be an electronic control means, e.g. a microprocessor, which is pre-programmed to provide, via the flow rate determining means and the valve actuation means, a dispense rate following a predetermined profile or flow curve. Thus the electronic control means can be programmed to provide specific varying flow rates for different beverages depending, for example, on their desired degree of carbonation and/or for different cup or glass sizes into which the beverage is to be dispensed.
The valve groove(s) may be, for example, of tapering V-shape and will, for convenience, hereafter be referred to as xe2x80x9cV-groovesxe2x80x9d and the valves of this general type as xe2x80x9cV-groove valvesxe2x80x9d, although it will be appreciated that the grooves may, if desired, have a different tapering cross-section, e.g. of circular, rectangular or other shape. The progressive increase or decrease in area of the groove flow channels can produce excellent linear flow through these V-groove valves. Moreover, V-groove valves have been found to be surprisingly effective in reducing the degree of carbon dioxide break out that can occur when a carbonated beverage is dispensed through a valve.
The valve closure member preferably comprises a substantially rigid piston, which may be of the same material as the housing, the latter preferably also being substantially rigid. They may be made of, for example, metal, plastics material or ceramic material. Suitable rigid plastics materials include, for example, acetals, and acrylonitrile-butadiene-styrene. The groove(s) may be, for example, cut or moulded into the material of the passageway wall or closure member by conventional means depending on the material used.
Preferably the grooves are formed in the passageway wall.
The closure member may carry one or more sealing rings to engage the wall of the passageway in the first position, i.e. the closure member may engage the wall of the passageway by means of the sealing ring(s) to close the outlet. Alternatively, sealing rings for this purpose may be located in the wall of the passageway. In a yet further embodiment the closure member and passageway may be a precision fit in the first position to close the outlet without a seal.
The valve passageway preferably comprises at least a portion in the form of a right cylinder with the closure member comprising a corresponding cylinder of outside diameter slightly less than the internal diameter of the passageway and, typically, the closure member having an O-ring seal attachment around its outer surface to seal against the passageway wall.
The actuation means to open and close the valve preferably comprises drive means for a piston or closure member, movement of the closure member to and fro in the passageway between the inlet and outlet of the valve determining the degree of opening. The drive means may be, for example, a lever mechanism, a stepper motor, e.g. of the pulsed magnetically-driven type, a proportional solenoid actuator; a diaphragm operated mechanism or the like.
The means to propel the beverage from its source through the valve to the dispense point may be any convenient means. For example, as are conventionally used, the means may be a pump or a source of pressurised gas.
Thus the invention provides a means of providing a dispense flow rate profile particularly suited to the particular circumstances of the beverage to be dispensed. A different flow rate v. time profile may be desirable for any particular beverage when dispensed into a small glass compared with dispense into a large glass and the control means can readily be programmed to provide the optimum profile for each circumstance. A slower dispense rate for smaller glasses will reduce splashing whereas a faster speed for large glasses will reduce filling time.
The flow rate profile may also be pre-programmed to avoid excessively abrupt flow changes at the beginning and end of a dispense. Thus, for example, a xe2x80x9csoftxe2x80x9d start and finish to the dispense may be programmed into the control means. In other words, instead of the dispense valve being rapidly moved from the fully closed to the fully open position on commencement and at the end of dispense, it can be gradually opened from fully closed to a partially open position and then moved rapidly to the fully open position and then towards the end of the dispense it can be moved rapidly from fully open to a partially open position and then be closed gradually from that partially open position.
By way of illustrative example only, for a dispense of ten seconds, the flow rate could be controlled to increase from zero to, say, 20 ml/sec over a two second period and then rapidly increased to a maximum flow rate of, say 160 ml/sec over a short period of time of about two further seconds, maintained at that maximum rate for about four seconds, then rapidly reduced to 20 ml/sec over a one second period and then reduced to zero over the final second. V-groove valves as used in the present invention are particularly amenable to such controlled opening and closing and, as indicated above, this is particularly advantageous when dispensing carbonated beverages.
The control means effectively monitors the flow rate and time and so can calculate the volume dispensed so far at any instant, the remaining volume to be dispensed, e.g. for a xc2xd liter total dispense, and hence the flow rate(s) then required to achieve the desired total dispense volume and time.
The dispense point, e.g. dispense tap, may incorporate a plurality of options, e.g. with a separate push button dispense operation for each option, whereby triggering of a particular option alerts the control means to activate the chosen dispense routine. Alternatively, a number of dispense taps, each for one or more specific dispense routines, may each be connected to a single control means.